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73 lines
2.8 KiB
73 lines
2.8 KiB
/***************************************************************************
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* Copyright (C) 2004-2005 by Daniel Clarke *
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* daniel.jc@gmail.com *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, write to the *
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* Free Software Foundation, Inc., *
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
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***************************************************************************/
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#ifndef TRAVERSER_H
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#define TRAVERSER_H
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#include "btreenode.h"
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/**
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Keeps persistant information needed and the algorithm for traversing the binary trees made of BTreeNodes, initialise either by passing a BTreeBase or BTreeNode to traverse a sub tree.
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Note that this is designed for traversing in the *reverse* way starting at the end of each branch
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in order to calculate the expression contained in the tree.
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@author Daniel Clarke
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*/
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class Traverser
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{
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public:
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Traverser(BTreeNode *root);
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~Traverser();
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/** Find where to start in the tree and return it also resets all the data related to the traversal. */
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BTreeNode *start();
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/** Finds the next node to move to and returns it. */
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BTreeNode *next();
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/** Returns true if we are on the left branch, false otherwise. */
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bool onLeftBranch();
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/** Returns the node on the opposite branch of the parent. */
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BTreeNode * oppositeNode();
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BTreeNode * current() const { return m_current; }
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void setCurrent(BTreeNode *current){m_current = current;}
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/** From the current position, go down the tree taking a left turn always,
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and stopping when reaching the left terminal node.
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*/
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void descendLeftwardToTerminal();
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/** It might occur in the future that next() does not just move to the parent,
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so use this for moving to parent
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*/
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void moveToParent();
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BTreeNode *root() const {return m_root;}
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protected:
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BTreeNode *m_root;
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BTreeNode *m_current;
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};
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#endif
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